1. Field of the Invention
The present invention relates to a high-frequency treatment instrument.
Priority is claimed on Japanese Patent Application No. 2006-153, filed on Jun. 1, 2006, the content of which is incorporated herein by reference.
2. Description of the Related Art
As a treatment method of removing a biological tissue such as a mucous membrane by the use of an endoscope, an endoscopic submucosal dissection (ESD) method of cutting out a normal mucous membrane around a pathological lesion portion and then dissecting a submucosal layer to remove or the like the pathological lesion portion so as to remove the pathological lesion portion generated on a surface of an alimentary canal is known.
Various treatment instruments are used for such kind of dissecting treatment. For example, a high-frequency treatment instrument having a knife portion as a treatment electrode at a distal end of a rod-shaped electrode portion housed in a sheath is known (for example, see Japanese Unexamined Patent Application, First Publication No. H08-299355).
By the use of the high-frequency treatment instrument described in Japanese Unexamined Patent Application, First Publication No. H08-299355, it is possible to dissect the submucosal layer by allowing high-frequency current to flow in the knife portion to cut out a mucous membrane contacting the knife portion.